Hydrangeas are one of my favorite plants, they are beautiful, can handle almost any soil and are pretty hardy.
However, I have noticed some people are asking ‘can hydrangea roots damage foundations’?
And indeed there does seem to be some concern about how invasive they are, and how quickly they can grow.
So I thought it would be a good idea to get to the root of the problem (pun fully intended).
So without further ado, let’s get started.
Can Hydrangea Roots Damage Foundation?
Hydrangea roots will neither damage foundations or pipes. The roots of a hydrangea are actually very slender and fibrous and are never going to be strong enough or thick enough to cause any damage. If you plant a hydrangea near your house make sure it is half its mature width plus one additional foot away. This is to give the hydrangea enough space to grow healthily, not because it can cause any damage to your foundations or pipes.
Are Hydrangeas Invasive?
Now I have seen some people say hydrangeas are invasive, they are not.
Some varieties can be very aggressive, spread quickly and quite frankly can be annoying (Annabelles I am looking at you), but that doesn’t mean they are invasive.
There seems to be a blurring of the lines and an idea that because a plant expands over time and gets a foothold in your garden that it is invasive.
That isn’t the case.
An invasive plant is defined as:
“An alien species whose introduction does, or is likely to, cause economic or environmental harm or harm to human health. Alien species means, with respect to a particular ecosystem, any species that is… 1) non-native (or alien) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.”
That is taken directly from the Federal Invasive Species Advisory Committee Policy.
So essentially an invasive plant is a non-native plant that has shown it can outcompete native plants in their natural environments to the point it can cause economic or ecological harm.
The hydrangea doesn’t fit these definitions, since it is native and doesn’t pose an ecological or economic threat in natural environments as it won’t escape into the wild.
So they can sometimes be a pain and be vigorous spreaders, by hydrangeas are not invasive.
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Are Hydrangeas Deep Rooted?
So do hydrangeas have deep roots? No, they are actually shallow-rooted.
They have a fibrous root system with no tap roots and no large roots. Their main roots are made of rhizomes and elongate to sprout at bud points, and usually remain within the top six inches of soil.
Whilst their slender roots might not penetrate deep into the earth, they do spread quite widely and can reach up to 10 feet (3m) depending upon the species.
Will Hydrangea Roots Damage Concrete Foundations?
Ok so now on to the main question of whether hydrangea roots will damage the concrete foundations of a house.
The short answer is no they won’t.
We’ve already discussed how slender and fibrous the roots of hydrangea are, and the fact they are not deep-rooted plants.
This means the roots of hydrangea are not strong enough or deep-seated enough to cause any damage to concrete foundations.
They are certainly never going to be thick enough to crack the sturdy foundation of a house.
One thing you might want to consider is the fact, that cement from foundation can leech lime for years.
So if you have moved into a newly built house and planted hydrangeas around it, the lime could turn normally blue hydrangeas pink.
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Will Hydrangea Roots Damage Pipes?
Another common concern when it comes to planting hydrangeas around a house is whether they will damage any pipes running under the house.
Again the answer is no, hydrangea roots will not damage pipes.
Most pipes these days are made of concrete or PVC tube, and even older clay pipes will be pretty much impenetrable to the relatively slim roots of a hydrangea.
The only time the roots of a hydrangea are likely to cause trouble for pipes is if there is already a problem with the pipe.
If the pipe springs a leak for another reason, then the hydrangea might invade it simply because any plant’s roots will grow toward a steady source of water.
But a hydrangea on its own will not force its way into an unblemished pipe.
How Far Apart Should You Plant Hydrangeas?
We alluded to this earlier, but the distance apart you need to plant hydrangeas depends on their species and variety.
At the very least they will need to be around 3 feet (1m) apart and at the most 13 feet (3.9m) apart.
To work out exactly how far apart your hydrangeas should be planted, work on the basis that they should be the width of one fully grown plant plus one extra foot apart.
So taking a bigleaf hydrangea as an example., these can grow anywhere from 6 to 10 feet (1.8m to 3m) wide.
That means you should leave a distance of 7 to 11 feet (2.1m to 3.3m) between them.
If you plant them too closely together a number of issues can arise, including:
- An increased risk of fungal diseases spreading due to lack of air and proximity of plants.
- Lack of moisture as your plants compete for water from the same patch of soil.
- Lack of nutrients for this very same reason.
For the most popular species the table below gives you an idea of how far apart they should be planted:
| Name | Width of a mature plant | Distance between plants |
| Bigleaf hydrangeas | 6-10 feet (1.8-3 m) | 7-11 feet (2.1-3.3 m) |
| Mountain hydrangeas | 2-4 feet (0.6-1.2 m) | 3-5 feet (0.9-1.5 m) |
| Panicle hydrangeas | 6-12 feet (1.8-3.6 m) | 7-13 feet (2.1-3.9 m) |
| Smooth hydrangeas | 3-5 feet (0.9-1.5 m) | 4-6 feet (1.2-1.8 m) |
| Oakleaf hydrangeas | 6-8 feet (1.8-2.4 m) | 7-9 feet (2.1-2.7 m) |
| Climbing hydrangeas | 5-6 feet (1.5-1.8 m) | 6-7 feet (1.8-2.1 m) |
Alternatively, you can use the excellent Hydrangea spacing calculator on the World of Garden Plants website.
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How Far Away From Your House Should You Plant Your Hydrangea?
Hopefully having read about their slender roots, it should have allayed any real fears when it comes to the issue of whether you can plant hydrangeas next to your house or not.
That said there are some guidelines on how far you should plant hydrangeas from your house, not because they pose any damage to your house but because you will want to ensure they have sufficient room to spread out, can get enough sun and air is able to circulate sufficiently.
It is pretty simple, you should plant your hydrangeas at a distance of half its mature width from your house, plus an extra foot so you can get in for maintenance and so the wall isn’t always damp.
Using the same species as above, this works out at:
| Name | Width of a mature plant | Distance from house |
| Bigleaf hydrangeas | 6-10 feet (1.8-3 m) | 4-6 feet (1.2-1.8m) |
| Mountain hydrangeas | 2-4 feet (0.6-1.2 m) | 2-3 feet (0.6-0.9m) |
| Panicle hydrangeas | 6-12 feet (1.8-3.6 m) | 4-7 feet (1.2-2.1m) |
| Smooth hydrangeas | 3-5 feet (0.9-1.5 m) | 2.5-3.5 feet (0.75-1m) |
| Oakleaf hydrangeas | 6-8 feet (1.8-2.4 m) | 4-5 feet (1.2-1.5m) |
| Climbing hydrangeas | 5-6 feet (1.5-1.8 m) | 2.5-4 feet (0.75-1.2m) |
Also remember your roof might overhang the hydrangea, if it does then you will need to ensure it receives adequate moisture, something that is very important for the first couple of years.
Final Thoughts
We have actually covered a fair bit here, but the main takeaways should be that if you are wanting to know if hydrangea can damage foundations, then the answer is no.
Neither will they cause any damage to your pipes (unless something else causes the pipe to split, then, like any plant, the hydrangea might worm its way in).
I think perhaps these questions get asked as some varieties of hydrangea, in particular Annabelles, spread and spread quickly.
And there is a worry they will cause damage if you plant them too close to your house, but I can assure you they won’t.
It is probably also why the question are hydrangeas invasive? Seems to be quite popular, but they aren’t invasive either.
Either way I hope this has put your mind to rest.